Process of making yarn from continuous rayon and staple fiber



Oct. 11 1938. L W BOOTH 2,132,524

PROCESS OF MAKING YARN FROM CONTINUOUS RAYON AND STAPLE FIBER Filed June21, 1937 Fig.1

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Patented on. 11, 1938 UNITED STATES PATENT OFFICE PROCESS OFMAKING YARNFROM CONTIN- UOUS RAYON AND STAPLE FIBER Leroy W. Booth, Sanford, Maine,assignor to Sanford Mills, Sanford, Maine, a corporation of MaineApplication June 21, 1937, Serial No. 149,332 9 Claims. (Cl. 118-69) Yfilaments is substantially retained in the finished yarn, such processesrequire great care and are' relatively expensive. These continuousfilaments,

particularly in the case of the rayon or artificial silk,- have alsobeen manufactured into yarn by first being cut or broken into stapleform and then passed through the usual processes employed in themanufacture of yarn from staplefiber. But in this latter case the lossdue to wastage and the expense involved in passing such continuousfilaments after being reduced to staple form through these preliminaryprocesses'is very considerable.

It is very desirable in the manufacture of yarn to produce a mixed orcomposite yarn composed both of fibers which were originally parts ofcontinuous filaments, such as the rayon fibers, and fibers which wereoriginally in natural staple form such as mohair, wool, cotton, etc.',and this has only heretofore commercially and successfully beenaccomplished by first reducing the continuous filaments to staple formand 'then mixing these with the natural staple fibers and carrying outthe usual processes performed in the manufacture of yarn from staplefiber.

While heretofore it has been proposed to form yarn entirely fromcontinuo'us filaments by breaking the filaments in roving form as theresult of a drafting operation, difficulties are presented due to theelectrified condition of the filaments and fibers, the tendency of thefilaments to slip in the grip of the rolls, the tendency of thefilaments as they break to whip back or curl up, the loss of fibersbroken at both ends between the rolls of the drafting frame, and thetendency to a beardy" formation. The present invention makes use of theprinciple of reducing the continue-as filaments to staple form bybreaking them as bythe action of a drafting frame but'carries on thisstep while a ribbon of the continuous filaments is slightly twistedtogether with a roving ojj'staple fibers so that as a result thestaple-fibers actas a carrier or support for the continuous filamentsduring the breaking operation. By this means a firm grip is secured uponthe composite strand so as positively and regularly to effect thebreakage of the continuous filaments; the whipping back or curling up ofthe continuous filaments as they break is substantially prevented; thedisturbance of the broken fibers because of their electrical conditionis substantially overcome, and the resultant yarn of mixed fibers is ofa uniform,- non-beardy, high character.

The nature and objects of the invention will more fully be understoodfrom the accompanying 1 description and drawing and will be particularlypointed out in the claims.

In the drawing: Fig. 1 is a view in side elevation, chieflydiagrammatic, of "a portion of an ordinary type of the drafting frameadapted for carrying out one step of the present invention.

Fig. 2 is a similar view of another frame which may be a spinning frameadapted for carrying out a further step in the preferred invention.

While the invention is adapted for making use of any form of continuousfilaments suitable for textile purposes, it is particularly useful inconnection with continuous artificial silk or rayon filaments. Suchcontinuous filaments are extensively manufactured from ,re-constitutedcellulose, as in the case of the viscose or cuprammonium processes, andalso from cellulose acetate or other organic derivatives of cellulose;the cellulose acetate filaments being very largely employed.

The invention is also adapted for making use of any fibers suitable fortextile purposes and already in ..s. aple form and preferably of suchfibers that exist naturally in long staple form such as mohair, wool,linen, etc. v

The yarn produced by this process is' a mixed or composite yarn, onecomponent being originally continuous filaments and the other componentbeing originally staple fibers. The relative proportion of thesecomponents may vary within wide limits, although the best results havebeen 'secured when the component of the originallycontinuous filamentsdoes not exceed 50%. g

The process of the invention may be carried out by any suitable meansbut preferably ordinary drafting and spinning frames capable of.maintaining a firm grip on the filaments and fibers and employed in yarnmanufacture are used with very slight alteration, such as frames of thetype employed in the Bradford system and illustrated in the drawing. Theframe illustrated in Fig. 1.may represent any of the drafting framespreceding the frame employed for the final drafting and spinningoperation, as, for example, the finisher frame which usually precedesthe roving frame, which in turn precedes the spinning frame. Thisfinisher frame is provided with the usual front or drafting rolls I and2 with the-bottom roll 2 of fluted steel and the top roll covered with acork or similar surface 3. The finisher frame at the rear is providedwith the usual series of back or gang rolls 4, 5, 6 and I. The gangrolls as usual are adjustable bodily toward-and from the front rollsandv all the rolls are positively driven, the front rolls being drivenat a higher peripheral speed than finisher frame in the usual manner,that is,

around the gang rolls as indicated, between the lower pair 6 and I,thence through the carrier rolls and thence between the front ordrafting rolls 2 and 3. The continuous'filaments in the condition inwhich they are produced are parallel and usually untwisted in the formof what is known as a'ribbon. Such a ribbon composed of the requirednumber of parallel filaments is led directly between the front ordrafting rolls I and.2. The ribbon of filaments and roving of staplefibers, after they emerge from the front rolls l and 2, pass through theusual guide eye I I and are wound on to a suitable bobbin or yarncarrier l2 in the usual manner, being given in this operation a slighttwist so that the strand or ribbon of continuous filaments and thestrand or roving of staple fibers are given a slight joint twist on theorder of three to four turns per inch as they are wound onto the yarncarrier.

The framerepresented in Fig. 2 is the next 40 drafting frame to whichthe composite strand the thus formed is passed and this frame, forexample, rnay be a roving frame of the usual type preceding the actualspinning operation or it may even be the final drafting and spinningframe. This frame has a similar construction to that shown in Fig. 1comprising the front rolls l3 and H, the carrier rolls l5, and the backor gang rolls IS, l1, l8 and I9. The composite strand now made up ofthecontinuous filaments and staple fibers twisted together, passes throughthis frame in the usual manner and the resultant roving passes throughthe guide eye 2| and is wound or spun onto the bobbin or yarn carrier22. The front rolls l3 and H as usual are run at a much higherperipheral speed than the back rolls so that a drafting .operation takesplace on the entire composite strand 2', the result of which is to breakthe continuous filaments of the ribbon into staple form, but as thisbreakage takes place while these filamentsare enveloped by or twistedtogether with the component of natural fibers,

the broken filaments are held against whipping back or curling up andare prevented as the result of the electrical action of the fibers fromsubstantial disturbance from their normal position in the compositestrand. Furthermore, the grip of the pairs of rolls at the frontand.back acting on the composite strand, that is, upon both thefilaments and the fibers, insures a firm grip so thatdeleterious'slippage is prevented. In fact,

tirely of staple fibers drafted and slightly twisted together, and afurther-twist is imparted in the usual manner as it is wound upon theyarn carrier If the roving has not been sufilciently attenuated to formthe desired yarn, further drafting and final spinning may take place allin the usual manner because the roving is-now entirely composed ofstaple fibers.

The distance between the front and back rolls of the frame shown in Fig.2, commonly known as the ratch,'depends upon the length of the staple ofthe staple flber component. 'Since the front and rear rolls must'beseparated a distance somewhat greater than the staple length of thestaple fiber sufficient to prevent any material breakage of the staplefiber, and since the elongation of the continuous filament is on theorder of to or less up to the breaking point, there need be little, ifany, change made from the position required for drafting the said staplefiber alone. No change in the relative speed of the front and rear rollsof the frame, such as shown in Fig. 2 where the breakage of thecontinuous filaments takes place, from that usually em ployed in thedrafting operation is necessary because the normal diiferential in orderto attenuate the roving as required in the yarn manufacture is so farbeyond anything required to elongate the continuous filaments to thebreaking point that the minimum limit need not be considered. Theelongation effected by the drafting operation is on .the order of 600%to 700%, while the maximum elongation of rayon filaments to the breakingpoint is on the order of 25% to 30%.

In these drafting frames of. the Bradford system the pressure betweenthe rolls is adjustable and may be varied as desired. The grip or biteof the rolls upon the composite'strand where the breakage of thecontinuous filaments takes place must be suflicient to prevent anyundesirable slippage between the roll periphery and the strand and toinsure breakage of the continuous filaments into the required staplelength. The continuous filaments, being more or less intermingled withthe staple fibers as the result of the twisting operation employed informing the composite strand, are not all gripped with equal pressure bythe rolls and consequently break unsymmetrically and in more or lessuneven lengths, thus resulting in a condition similar to that of thestaple fiber itself.

It is desirable that the denierof the continu-' ous filament should notbe greater than that of the corresponding size of the'staple fiber. Forexample, when cellulose acetate filament is mixed with mohair, a 10denier of the acetate filament which corresponds closely to the size ofmohair fiber has producedhighly satisfactory results.

It will thus be seen that when the composite strand composed of aribbonor strand of the continuous filaments and a roving of the staple fibersslightly-twisted together passes through the step of the processillustrated in Fig. 2, there is applied successively and continuouslytothis strand between points separated by a distance somewhat greaterthan the staple length of the staple fibers a longitudinal strainsufficient to break the continuous filaments extending between saidpoints and that the staple fibers act as a carrier' for the continuousfilaments as they break into staple length and are'drafted alongtherewith.

Having thus described the invention, what is amass-i claimed as new; anddesired to be secured'by letters I atent is:

-1. The process of forming yarn from both continuous filaments andstaple fibers which comprises slightly twisting together a ribbon of thecontinuous filaments and a roving of the staple fibers and drafting thecomposite strand thus formed while maintaining a ratch greater than thestaple length of the staple fibers and a draft strain sufficient tobreak the continuous filaments, and thereafter spinning the draftedcomposite roving withtall its fibers thus in staple forminto yarn.

2. The process of forming yarn from both continuous filaments and staplefibers which comprises slightly twisting together a ribbon of thecontinuous filaments and a roving of the staple fibers, successively andcontinuously ap-. plying to the composite strandvthus formed betweenpoints separated by a distance somewhat greater than the staple lengthof the staple fibers a longitudinal strain sufficient to break thecontinuous filaments extending between said points, and thereafterspinning the composite roving with all its fibers thus in staple forminto yarn.

3. The process of forming yarn from both continuous filaments and staplefibers which comprises slightly twisting together a ribbon of thecontinuous filaments and a roving of the staple fibers, drafting thecomposite strand thus formed to secure an elongation thereofsubstantially greater than that elongation of the continuous filamentswhich is possible without breakage, and thereafter spinning the draftedcomposite roving with all its fibers thus in staple form into yarn.

4. The process of forming yarn from both continuous rayon filaments, andnatural staple fibers which comprises slightly twisting together aribbon of the continuous filaments and a roving of i the staple fibersand drafting the composite strand thus formed while maintaining a ratchgreater than the staple length of the staple fibers and a draft strainsuflicient to break the continuous filaments, and thereafter spinningthe, drafted composite roving with all .itsfibers thus in staple forminto yarn.

5. The process of forming yam from both continuous rayon filaments andnatural staple fibers which comprises slightly twisting together'a rib-'bon of the continuous filaments and a roving of the staplejibers,drafting the composite strand thus formed to secure an elongationthereof substantially greater than that elongation of the continuousfilaments which is possible without breakage. and thereafter spinningthe composite roving with all its fibers thus in staple form into yarn.

6. The process of forming yarn from both continuous cellulose acetatefilaments and staple fibers which comprises slightly twisting together aribbon of the continuous filaments and a roving of the staple fibers anddrafting the composite strand thus formed while maintaining a ratch,greater than the staple length of the staple fibers.

and a draft strain suflicient to break the continuous filaments, andthereafter spinning the drafted composite roving with all its fibersthus in staple form into yarn.

7. The process of forming yarn from both I continuous cellulose acetatefilaments and staple animal fibers which comprises slightly'twistingtogether a ribbon of the continuous filaments and a roving of the staplefibers and drafting the composite strand thus formed while maintaining aratch greater than the staple length of the staple fibers and a draftstrain suflicient to break the continuous filaments, and thereafterspinning the drafted composite roving with all its fibers thus in stapleform into yarn.

8. The process of forming yarn from both continuous cellulose acetatefilaments and natural staple fibers which comprises slightly twistingtogether a ribbon of the continuous filaments and a roving of the staplefibers, successively and continuously applying to the composite strandthus formed between points separated by a distance somewhat greater thanthe staple length of the staple fibers a longitudinal strain sufficientto break the continuous filaments extending between said points, andthereafter spinning the composite roving with all its fibers thus instaple form into yarn.

9. The process of forming yarn from both continuous filaments and staplefibers which comprises slightly twisting together a ribbon of thecontinuous filaments and a roving of the staple fibers and then passingthe composite strand thus formed through successive pairs of rollsdriven atdiiferent peripheral speeds, the bites of which are separated adistance greater than the length of the staple of the staple fiber, thedifferential in speed between said pairs of rolls being sumcient tostretch the continuous filaments past the breaking point but notsufficient to separate the strand, and the grip of the rolls of eachpair on the strand being sufiicient to prevent substantial slippagebetween their periphcries and the strand.

; LEROY

